Video Output Switcher Control¶
The output sysfs class driver provides an abstract video output layer thatcan be used to hook platform specific methods to enable/disable video outputdevice through common sysfs interface. For example, on my IBM ThinkPad T42laptop, The ACPI video driver registered its output devices and read/writemethod for ‘state’ with output sysfs class. The user interface under sysfs is:
linux:/sys/class/video_output # tree ..|-- CRT0| |-- device -> ../../../devices/pci0000:00/0000:00:01.0| |-- state| |-- subsystem -> ../../../class/video_output| `-- uevent|-- DVI0| |-- device -> ../../../devices/pci0000:00/0000:00:01.0| |-- state| |-- subsystem -> ../../../class/video_output| `-- uevent|-- LCD0| |-- device -> ../../../devices/pci0000:00/0000:00:01.0| |-- state| |-- subsystem -> ../../../class/video_output| `-- uevent`-- TV0 |-- device -> ../../../devices/pci0000:00/0000:00:01.0 |-- state |-- subsystem -> ../../../class/video_output `-- uevent